Asthma in the intensive care unit: A review of patient characteristics and outcomes.

Abstract

Background: Most asthma-related deaths occur in low- and middle-income countries, and South Africa (SA) is ranked fifth in global asthma mortality. Little is known about the characteristics and outcome of asthma patients requiring intensive care unit (ICU) admission in SA.

Objectives: To identify and characterise patients with acute severe asthma admitted to the respiratory ICU at Groote Schuur Hospital, Cape Town, SA, in order to evaluate outcomes and identify predictors of poor outcomes in those admitted.

Methods: We performed a retrospective descriptive study of patients with severe asthma admitted to the respiratory ICU at Groote Schuur Hospital between 1 January 2014 and 31 December 2019.

Results: One hundred and three patients (110 admission episodes) were identified with an acute asthma exacerbation requiring ICU admission; all were mechanically ventilated. There was a female preponderance (53.6%; n=59/110), with a median (range) age overall of 33 (13 - 84) years. Of all admissions, 40 (36.4%) were current tobacco smokers and 16 (14.5%) patients with a history of substance abuse. Two thirds (60.0%; n=66/110) of the patients were using an inhaled corticosteroid (ICS). No predictors of mortality were evident in multivariate modelling, although those who died were older, and had higher Acute Physiology and Chronic Health Evaluation (APACHE II) scores and longer duration of admission. Only 59 of the surviving 96 individual patients (61.5%) attended a specialist pulmonology clinic after discharge.

Conclusion: Among patients admitted to the respiratory ICU at Groote Schuur Hospital for asthma exacerbations, there was a high prevalence of smokers and poor coverage with inhaled ICSs. Although mortality was low compared with general ICU mortality, more needs to be done to prevent acute severe asthma exacerbations.

Study synopsis: What the study adds. Intensive care unit (ICU) admission represents the most severe form of exacerbation of asthma. South Africa (SA) has a very high rate of asthma deaths, and this study demonstrates that admission to an ICU with a very severe asthma exacerbation frequently results in a good outcome. However, many of the patients admitted to the ICU were not adequately treated with background asthma medications prior to their admission. Implications of the findings. Death from asthma should be avoidable, and admission to an ICU is not associated with high mortality. Patients are therefore likely to be dying at home or out of hospital. Better education and access to medication and early access to health services rather than improved in-hospital care would potentially alter SA's high asthma mortality.